1. Technical Field
One or more embodiments of the present invention relate to compounds for organic light-emitting devices and to organic light-emitting devices including the compounds.
2. Description of the Related Art
Organic light-emitting diodes (OLEDs) are self-emitting devices having advantages such as wide viewing angles, good contrast, quick response times, high brightness, and good driving voltage. OLEDs can provide multicolored images.
In general, an OLED has a structure including a substrate, an anode, a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode, which are sequentially stacked on the substrate. In this regard, the HTL, the EML, and the ETL are organic thin films formed of organic compounds.
An operating principle of an OLED having the above-described structure is as follows.
When a voltage is applied between the anode and the cathode, holes injected from the anode move to the EML via the HTL, and electrons injected from the cathode move to the EML via the ETL. The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.
The most important factor for determining the luminous efficiency of an OLED is the light-emitting material. Fluorescent materials or phosphorescent materials have been used as the light-emitting material, but OLEDs including such light-emitting materials do not exhibit satisfactory efficiency, driving voltage and lifetime.